Polls can be unstable. Up until the last moment, Jimmy Carter was leading Ronald Reagan in 1980. And in the past two weeks, President Obama has started to pull ahead of Mitt Romney.

Romney's campaign is hoping for a reversal of fortune within the next 50 days or so. But judging by the way some of the biggest pro-Republican superPACs are spending their money, it could be a sign that they think they might have a better chance retaking the Senate than winning the White House.

Crossroads, for example, a superPAC founded by Karl Rove, is working to turn several Democratic Senate seats into Republican ones in Florida...

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UNIDENTIFIED WOMAN: And time to send a message to Bill Nelson, who voted for the wasteful $800 billion stimulus he said would jump-start the economy.

RAZ: ...in Ohio...

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UNIDENTIFIED MAN #1: Coming to you this year, the health care takeover. Taxes on Ohio businesses that could kill jobs. Sheriff Brown gives two thumbs-up.

RAZ: ...and in Virginia.

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UNIDENTIFIED MAN #2: Tim Kaine left Virginia for Washington and was a cheerleader for massive spending.

RAZ: Our cover story today: Are some of the big money GOP superPACs shifting strategy away from the presidential race and into the congressional ones? In a moment, we'll put that question to a senior member of the Crossroads superPAC, but first to NPR's Ari Shapiro who's been on the campaign trail with Mitt Romney these past two weeks.

ARI SHAPIRO, BYLINE: I think this campaign has had an extremely difficult week. It's hard to compare what it was like at moments in the primary, for example, when Newt Gingrich dominated in South Carolina to now when it's the general election against to Barack Obama. But the fact is, in addition to the tough poll numbers, they had this sort of unexpected crisis in Libya where even some prominent Republicans criticized Romney's handling of it.

In addition, there was some criticism about the amount of campaigning that he's been doing. It seems like less than other candidates at this point in the race. So you had a few different fronts in which the Romney campaign was on the defensive. And the question is, will they bounce back?

RAZ: We are going to hear in just a moment from Jonathan Collegio, who works for American Crossroads, the Karl Rove-founded superPAC. We've talked to some Republicans who've told us sort of on background that, you know, even if Romney loses, they could eke out a victory with the Senate. But it was interesting because you are starting to hear that unnamed Republican saying, well, you know, the White House may not work out, but we may claim victory in other places.

SHAPIRO: There's been a really interesting push-pull through this entire campaign between the Republican establishment and Mitt Romney where Mitt Romney has always sort of been the guy who had the endorsements, who had the money, who was next in line, but who the Republican Party was always a little bit uncomfortable with, whether it was the Tea Party base or whether it was evangelicals who were suspicious of a Mormon candidate or whether it was just somebody who said he doesn't have the charisma of a Mike Huckabee. So this theme we're hearing now from Republicans of even if Mitt Romney doesn't win the White House is not a new theme.

RAZ: Yeah. Ari, I know it's an art, not a science, but are you getting any sense from members of the Romney team that they are getting a bit defensive? Or does it seem like everything is under control and everybody's operating as usual?

SHAPIRO: Well, there was a senior aide who told me that their internal polls are far more favorable than the public polls that the American people are looking at. You don't say that if you're not feeling a little bit defensive. They know they need to stage some kind of a comeback. They're putting a lot of faith in that being the debates that Romney has spent a lot of time preparing for. And that may be the last best chance for Mitt Romney to really change the dynamic of this race, and that's what his campaign is putting a lot of stake into.

RAZ: This past week, something mysterious happened - two of the biggest superPACs supporting Mitt Romney went dark. They didn't run any ads. And many reporters covering this story haven't been able to figure out why, including Noam Scheiber with The New Republic.

NOAM SCHEIBER: Now, there's any number of reasons why a superPAC could go off the air. They're just re-evaluating, recalibrating, trying to figure out what worked, what didn't, but it was a moment that would give you reason to recalibrate, given Obama's post-convention bounce. He's looking like he's got persistent leads in Ohio, which is obviously a key Electoral College state. But not just Ohio. It looks like Florida is looking, you know, I think early on, people thought Obama would just feint to Florida and the Romney campaign would eventually lock it down.

That's not really happened, and we've actually seen the reverse. Obama is building this persistent lead, and the Obama campaign is really starting to invest a lot of money in Florida. So I think the superPACs, if nothing else, want to see how that whole picture shakes out before they decide where they're going to allocate their resources going forward.

RAZ: Have you gotten a sense from some of these superPACs, particularly the pro-GOP superPACs, that they have come to a conclusion that maybe Romney won't win, but that they can still eke out a victory by pouring money into Senate campaigns to make sure that the GOP captures the Senate?

SCHEIBER: Well, I think you have to do this indirectly. There are some places where it's impossible to tell, because even if they were giving up on Romney in Ohio, they would still try to target the Senate race. Same thing in Virginia. The places I think you would look are places like Indiana, Montana, North Dakota even. Races that at the beginning of the cycle, the GOP thought these were going to be pretty reliable wins. If this were developing, you would start to see a lot more money being thrown at states like that.

You know, I mean, look. Ohio and Florida, they're going to keep spending money in those states even if Romney's looking incredibly grim, not just because there are competitive Senate races, because they've raised so many hundreds of millions of dollars. Where else are you going to spend it, right?

RAZ: About 50 days before the election now, what kind of strategy shift do you think we can expect to see from some of these superPACs in the coming days and weeks?

SCHEIBER: Well, I do really think it is these other Senate races. They may even take a crack in a place like, you know, Maine. You have New Mexico, which is, you know, as of 2004 was a pretty close place partisan-wise but has since then kind of tilted toward the Democrats. But I could see Republicans investing a little more money in a New Mexico Senate race. The calculus being, well, Senate races, you know, are places where half a million dollars could really turn the whole proposition and, you know, as long as you're sitting on $500 million and this presidential race is not looking like it's trending your way. It's worth a shot.

RAZ: That's Noam Scheiber. He covers politics for The New Republic. Now, if Mitt Romney doesn't win the White House, Republicans believe they could still eke out a victory by retaking the Senate, which is now controlled by Democrats.

JONATHAN COLLEGIO: Democrats have twice as many seats that they're defending in the elections of 2012 as Republicans in the Senate, and Republicans need to pick up a net of four seats in order to win.

RAZ: That's Jonathan Collegio, communications director for American Crossroads, the pro-GOP superPAC founded by Karl Rove. He says in the next few weeks, there could come a time when some conservative superPACs decide the presidency isn't worth the fight.

COLLEGIO: In theory, yes, but we're nowhere near that at this point. We have a goal, a fund-raising goal for the 2011-2012 cycle of approximately 240 to $300 million. We always thought that we would spend a majority of that on presidential level advocacy, both issue advocacy and political advocacy. And I don't think a serious observer could look at that map right now and say that this is not highly competitive. National polls have it within one or two points. And these state-by-state polls, everywhere where Romney has to win is within the margin of error.

RAZ: But in theory, if not in fact, I mean, if your resources were to focus on winning the Senate and Obama was re-elected, President Obama was re-elected, presumably the congressional Republicans could thwart an Obama agenda for at least two years and most likely four years. Could that also be a scenario that would be advantageous from your point of view?

COLLEGIO: Oh, absolutely. And we've actually dedicated - we're directionally looking at spending about $70 million on Senate level advocacy. So a significant amount of the Crossroads group's expenditures are going to be dedicated toward the House and the Senate.

RAZ: Let me ask you a question about tracking the money because, of course, your opponents, I mean, pro-Democratic groups, are also spending money. How do you track how they're spending money to figure out where you need to be spending money?

COLLEGIO: A couple of different ways. The first way you would look is if an ad is classified as a campaign ad by the Federal Elections Commission, you would see reports of where those expenditures had taken place. The other way you would do it is there are services where you can look at the types of advertisements that are going on television. I could see how much Procter & Gamble is spending to promote one of its products, and I can also see how much the Democratic National Committee is spending to promote one of its candidates.

RAZ: How much does that influence how you guys spend?

COLLEGIO: Oh, absolutely. We go over those reports every day. You kind of look at it as a giant, sophisticated chess game.

RAZ: And they're presumably doing the same thing.

COLLEGIO: They are doing the same thing, yeah. We will get - and, in fact, sometimes I will hear from reporters about where money is going before I hear from the tracking services, because if they want to make news about how they're going to be strategically placing money someplace, sometimes it'll get leaked to a reporter before it gets leaked publicly.

But a lot of it is a, you know, a lot of it is a strategy that we keep close to our vest. We do work with a lot of other like-minded groups to make sure, for example, that there's no duplicity in spending. You know, if Crossroads is going to be on the air in Florida with an ad, we want to make sure that in that same week, another group doesn't have an identical message on the air because that would be - you'd lose some of the effectiveness of the money going on. So we do share those plans with other like-minded groups.

RAZ: We've had Bill Burton on the show, who runs Priorities USA, and he kind of created this inspired by Karl Rove. It's a pro-Obama superPAC. It has about a third the amount of money you guys have. I mean, does American Crossroads sort of look out at particularly PACs like Priorities USA and other groups and say, man, we are - we're just killing it. I mean, we don't really have any serious competitors?

COLLEGIO: Oh, I think that there are competitors, but maybe they're not the competitors that people would think of at first blush. Labor unions are basically the kind of juggernaut on the left that we sought to balance out with our spending on the right in 2010. You also have to look at groups like MoveOn.Org and America Coming Together.

RAZ: Are they spending a whole lot this year?

COLLEGIO: No, they're not. But just as Bill Burton could say that he got the idea from American Crossroads on forming the Obama superPAC, we got a lot of those ideas from how the Democrats tried to defeat President Bush in 2004. Remember, they spent $200 million of outside money trying to defeat President Bush in 2004.

RAZ: So you guys are all getting ideas from each other.

COLLEGIO: Yeah.

RAZ: You should have a big party.

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RAZ: At the end of all this, because it is, I mean, part of it is a game. I mean, we are talking about a strategy to win, but there is a lot of strategy involved.

COLLEGIO: It's a lot. It's a giant chessboard and every move that you make has implications, not only with where you're moving, but how it impacts the spot that you left.

RAZ: That's Jonathan Collegio with the pro-GOP superPAC American Crossroads. By the way, conservative outside groups, including superPACs, have outraised pro-Democratic ones by nearly four times.

Coming up, more politics. How celebrity Rabbi Shmuley Boteach wants to bring some shalom in the home to Capitol Hill. Stay with us. It's ALL THINGS CONSIDERED from NPR News. Transcript provided by NPR, Copyright NPR.